In our shop, my boss is the VP of IT and I am his assistant. At ~55 desktops and ~65 employees, we host our own mail server. Yeah. Qmail on FreeBSD. Anyway, one his favorite refrains when someone has pretty much any email problem or question is that email is "not a guaranteed delivery mechanism." What does he mean by this? When you send an email you're just tossing it up in the air and hoping it will land where you want it to?

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To use an analogy, it's the same as sending a letter via USPS or any other postal carrier that doesn't use tracking numbers. You, as the sender, have no guarantee of delivery. Your mail could be lost on the way, received and thrown in the trash, used to heat a house, forwarded onto another address. Who knows.

The same applies to email.

Unless the receiver replies back, you have no way of knowing if they received the message.

I believe what he means is that there are a number of factors that can prevent a message from being delivered to its intended recipient. A mail message has to pass from the local mail client - through the outbound mail server, possibly through a firewall that's filtering outbound mail, possibly through a smart host, through a switch or firewall at the receiving end, to the recipient's mail server (or to the recipient's ISP and then on to the final recipient mail server), and then finally to the recipient's mail client. Each point in the process presents a potential place where a message could get lost. Sometimes, a firewall, DNS record, or mail server is mis-configured. Sometimes, the recipient mail server is offline due to network issues. Sometimes, a sender's mail server is blacklisted due to issues not yet discovered by the administrator (for example - if a computer on the local network gets infected & turned into a spam bot). Your firewall logs & mail server logs can reveal potential problems so that you can ensure that these issues don't exist locally on your network.

....When you send an email you're just tossing it up in the air and hoping it will land where you want it to?

Yes.

Consider US mail, registered mail, and registered & certified mail. Spam siutation has much reduced the reliability of email, as failed email (or caught in spam filters) don not even sent courtesy notification anymore.

"Read receipt" is an option, but not mandatory to be sent by the recipient. Exchange has mechanisms for verifying delivery within the same Exchange server.

Nothing in life is guaranteed, other than your going to die at some point, as previously mentioned it is like sending a letter in the post. 9 times out of 10 it will arrive as intended but there is always that 1 in 10 that will go missing. Email is the same with blacklists, spam filters, firewalls et al.

I wish I could use that line. I have to keep things working, even though all users have kept every single email they've ever received, and get upset when something is deleted from their Trash. At least once a week (if not more) I have to go digging through the server logs looking for an email someone was expecting and hasn't received yet.

I wish I could use that line. I have to keep things working, even though all users have kept every single email they've ever received, and get upset when something is deleted from their Trash. At least once a week (if not more) I have to go digging through the server logs looking for an email someone was expecting and hasn't received yet.

You need upper management support to put limits on space allowed per user. I know they have gotten spoiled with 15GB available from gmail and such, but you ain't Google.

If the users start not being able to send/receive email, they just might start cleaning up their mailboxes and taking this a bit more seriously.

Of course, I can almost guarantee that your upper management are amongst those who retain everything and complain loudly when they are running out of space, right?

Perhaps start saving every piece of junk snail mail you get at work and at home and start piling it up around your desk as a visual aid. In a couple weeks they might start getting it? At least once the piles are high enough they won't be able to find you to whine at.